tonight, the reset for mitt romney, or so they hope coming off a bad weeks, unleashing a new attack on president obama, regarding the chaos in the east. and fighting breast cancer, what they hope can be a new breakthrough in a new roadmap to more effective teaching. and education nation summit, what is coming to just about every school in the country. question is, are teachers and students ready for what is on the way. a broken heart, could it really be fatal? tonight, the doctors who say yes and warn that women have the most to worry about. and the panda, why it is proving so difficult to save these animals. this is nbc nightly news with brian williams.

good evening, if the race for president seems to have an urgency not fully supported by the calendar, then think of it this way. there are roughly a thousand hours to go before the election. every day and moment counts for the incumbent president and the man trying to unseat him. while both men have squared off in separate interviews over the last 24 hours, the first debate is still at least week away. and coming off a bad week, the romney campaign is anxious for traction. we begin tonight with chuck todd, our white house political correspondent. >> reporter: undeterred by a recent rocky stretch, mitt romney campaigned in colorado, insisting all is well with his campaign. >> we'll win, polls go up, some down. >> reporter: it is an aggressive

attack, answering questions about whether or not the recent middle east uprising gave him any doubt about the arab spring. >> it is the right thing to do to align ourselves with democracy. and i was certain and continue to be certain that there will be bumps in the road. >> reporter: romney seized on the phrase "bumps in the road". >> we just had an ambassador killed, problems in egypt, and the race for the president, iran is on the edge of problems. pakistan, i don't consider these bumps in the road. >> reporter: the white house dismissed the criticism. >> there is a rather certain desperate attempt to grasp it, words and in that case that is profound. >> reporter: the campaign unveiled a new attack, the tv

ads, releasing mitt romney's political tax returns with the remark that 47% of middle americans don't pay taxes. >> he wouldn't release his taxes for 2010, maybe instead of attacking others for taxes, romney should come clean on his. >> reporter: the president traveled for meetings at the united nations. but the first effort, a meeting with the first lady. the appearance and the slimmed down schedule included no one-on-one meetings with other world leaders. >> the fact of the matter is, the president does not wait for an annual meeting to have consultations with the foreign leaders, and it will continue. >> reporter: you know, brian, by contrast with 2004, the president had multiple meetings in india, iraq and afghanistan, that election was about national security. >> seems they should take advantage of the city being shut down for a couple of days, chuck todd with us. and overseas to the front

lines in afghanistan, where the drawdown of u.s. troops is getting a lot of attention, but lately it has been overshadowed by the insider attacks and the toll it has taken on american lives. lester holt is in kandahar where he talked one-on-one with the u.s. and coalition forces. >> reporter: brian, good evening, with the war about to enter the 12th year, questions remain about the taliban resistance. but the man in charge of the war says the strategy for america getting out in the year 2014 is on track. it is quickly becoming put-up time for afghan forces and crunch time for the american commander overseeing the transition. >> reporter: what keeps you up at night on this job? >> the time, the amount of time remaining. >> reporter: time between now and 2014? >> that is correct, we have a lot of work to do.

>> reporter: the u.s. and nato forces have trained more than 300,000 troops, taking the lead in combat operations. but threatening that, a deadly spike in insider attacks, afghan forces turning on their nato partners, 51 allied troops including 31 americans have been killed in such attacks so far this year. in a meeting today, the colonel acknowledged the existence of a training campaign. >> the taliban recognizes this is an opportunity for them to try to split us apart. we'll work very hard to stop that. >> reporter: the soldiers have to sleep with one eye open, doesn't that undermine the whole cohesion of the unity of the military? >> it does, and we have to work very hard to eliminate that threat. >> reporter: that includes efforts on the u.s.-afghan

training activities, improved betting of afghan recruits. but taliban fighters continue to demonstrate their resolve in other ways, recently attacking, destroying airplanes and killing two americans. >> it was not something we expected, but those types of attacks will come from time to time. >> reporter: the u.s. officials admit the taliban will likely continue the violent attacks even after the americans leave. >> would you expect the u.s. combat operations, if even only in a special forces, special operations role, to continue past 2014? >> the intent is our relationship will be a training and advisory relationship. it ends in december, 2014. >> reporter: within a few months, general allen will issue his recommendation to president obama as to whether or not to cut troops here again in the coming year. he says he will make that recommendation based on conditions on the ground. but brian, he is optimistic.

>> lester holt, in kandahar tonight, thank you. in this country tonight, there is health news getting some attention this evening, about breast cancer. and what is being called a new road map for understanding this disease. and coming up with more targeted treatments. more on this story with our chief correspondent robert bazell. >> reporter: scientists know there are several biological path ways that lead to breast cancer. but the roadmap had gaps. this latest research fills in many of them. opening up the possibility of entirely new personalized treatments. >> this is really a giant step towards understanding the fundamentals of what breast cancer is, so that we can develop new, effective therapies, one patient at a time. >> reporter: the research is part of a giant program, to analyze the thousands of changes in dna and cells that lead to all sorts of cancer.

and it provides the evidence that breast cancer is not one disease, but four major types and many sub-types. this means that many drugs on the market to treat leukemia, melanoma, and other cancers, say that patients need to know that while results are exciting, clinical trials are still needed. likely years. >> this is not something we can all take action on tomorrow in the clinic, but it is how we'll put together our next round of therapies and how we're going to move forward to change this disease. >> reporter: with this wealth of new knowledge, scientists are moving towards the day when they will have treatments tailored towards every type of cancer, to fix the program, to learn what is broken. robert bazell. and the new york public library has been transformed for this year's education nation

summit, which involves big names in the education world, including the secretary of education, arne duncan, and former secretary of state, condoleeza rice, this is the second straight year and the need is great. americans are 14th in reading, 17th in science, 25th in math, among 34 countries at the top. this summit's focus is on solutions, one of the big topics today. how the curriculum in our schools is about to change in a big way. our chief education correspondent, rehema ellis is at the new york public library tonight. good evening, rehema. >> reporter: good evening, brian, the numbers you just mentioned tell a clear story, which is why the nation's governors adopted the common core curriculum. this new, tougher more demanding standard of learning is generating buzz at the summit, as teachers are gearing up to teach a new way.

at this elementary school in louisville, all 361 students are encouraged to think big. >> every day at jba is one day closer to? >> college. >> college. >> reporter: ranking near the bottom on standardized tests, kentucky was quick to incorporate the tests, a blueprint for english and math, adopted by every state. while there is no common curriculum, this raises academic standards nationwide. and for the first time, an a will mean the same thing for students everywhere. >> so a student moving throughout kentucky will be expected to learn this same thing. and that is important, and students moving state to state will have a common expectation of what they're supposed to learn. >> reporter: teachers here at jb atkinson elementary school in louisville, will help them

implement critical thinking. reading books like charlotte's web, children don't just re-cap the story, but like detectives, use the text as evidence to support their opinions about it. math students won't just solve equations. they will work in groups to analyze real world problems such as how do stores use averages to calculate how much merchandise they need? >> you got kids engaging with the problem-solving. >> reporter: teachers prepping for common core have a lot to learn before it goes nationwide in 2014. >> every teacher i have started working with was overwhelmed at the transition between how we used to teach, and the common course standards. >> get out your green folders. >> reporter: still, some welcome it. >> before common core, teaching was a lot about a tech list. but now, you're really looking

at where are your students and how can i design instruction to get them what they need. >> reporter: a new way to create a common standard of high expectations. but some critics worry that a lot of teachers are not ready. the architects of common core say there could be a rocky transition period. some kids could take years before they measure up to the new benchmarks of learning and thinking. rehema ellis, not far from where we are in midtown manhattan. and stay tuned tomorrow, two exclusive interviews, president obama speaks with savannah guthrie, i'll sit down with governor romney to hear out their ideas on education. it is all part of our continuing coverage on the network and cable and on the web. still ahead for us tonight. we have all heard the expression, "dying of a broken heart." well, tonight what experts are learning about the power of sadness.

and working hard to save a great and beloved species.

a family obituary in the new york times announcing the death of the mother of christi brinkley said her heart never survived losing her husband, who died before her by seven weeks. that is very common after the death of a long-time spouse.

but is that worse than a medical condition, and could it be fatal as it often appears to be? our report from our chief medical expert, nancy snyderman. you're constantly waiting for somebody to come out and talk to you, the stress hormones are off the charts. >> i thought i was doing fine and handling it very well. >> reporter: but she wasn't. >> i remember coming, and standing by the nurse's station, talking to someone. and as i was talking -- i said wow, i really feel dizzy, and remember grabbing onto a counter and just trying to hold on for support. and at that moment, a black cloud, a curtain just came over my eyes, shaking, it was the last thing i remember. >> reporter: cindy was in full cardiac arrest, suffering from broken heart syndrome. 90% of the patients who

experience it are over the age of 55. >> we think as women age, their hearts and small blood vessels around their hearts become more reactive to the stress hormones, so stress you may experience at 25, when the estrogen levels are higher, could be different. >> reporter: this sent a signal to her glands, unleashing the surge to her blood stream, rushing to her heart. it paralyzed part of it, caused it to balloon out like this, and then shut down. >> there are cases of people dying from this condition, and when i'm asked can you die from a broken heart? we say absolutely yes, you can. >> reporter: cindy and joel both recovered, and now celebrating life's simple pleasures have taken on new meaning. >> you don't sweat the small stuff.

you live to enjoy life. >> enjoy each other, we're grateful for every moment we have is. >> this is not a heart attack, but the symptoms are like one. heart attacks are caused by blockages, this is simply a case of the heart being stunned by all the chemicals rushing to it. it is a temporary problem and the heart usually recovers completely if it is recognized in time, brian. the important thing is to recognize it. and i think they're under-recognized in the country. >> one of the true enduring medical mysteries. when we come back, a bad marketing decision. and tonight, one store is paying the price.

apple announced today it sold 5 million iphone 5s over the weekend, a huge demand. this may not help matters, a

riot broke out by a plant owned by one of apple's main chinese contractors, workers were involved in the fight. there was damage to the dorm, the area shut down for the time being. they supply parts for all the major electronics workers, 71,000 people work at that one individual plant. and a european plant called villa is under fire for what may not have been the smartest marketing idea, peeled bananas, in plastic trays with plastic shrink wrap, here is the problem, they come wrapped in one of the best ideas ever. locks in the freshness until you're ready to eat. the villa food chain got hammered, and have withdrawn their offering. and kerry walsh jennings was five weeks pregnant at the games.

she said she felt different in the games while throwing her body around. she and misty may treanor, now three-time gold medallists. and homeland security did very well for show time, hbo won a boat load of emmys. mad men got turned away for best drama. the other story, the nfl game on nbc won the night in the ratings by a pretty healthy margin, over what is routinely billed as tv's big night in hollywood. up next for us tonight, from new york, the fight to save the baby pandas. why there are so few and far between in this day and age.

finally tonight, washington, d.c. was a very sad place this weekend, with a lot of sad children all of whom had been so excited, along with their parents, at the birth of the new panda cub at the national six days. doctors say it died of a liver disorder, and for that entire species, survival is difficult, even when helped along by the rest of the experts in the world. our report by chief

correspondent ann thompson. >> reporter: this is the face that has stolen thousands of hearts. the now two-month-old panda born at the san diego zoo. >> they're so cute when they were little babies. >> reporter: when first born, pandas are pink, hairless and the size of a stick of butter, with the mortality rate high in captivity, this is a miracle. >> they're an endangered species, so having this for the wild population. >> reporter: the panda numbers are threatened because the bamboo forests where they live and eat are being cut down for farming and development. today, only 1600 giant pandas live in the wild in southern china, with 300 in captivity, including those outside of mainland china. >> pandas are amazing creatures.

>> reporter: they have driven chinese scientists to extreme, donning panda suits to introduce them to the wild, showing tapes of others mating. even turning to blue pills to help them with what should come naturally. why do they have trouble mating? first, they are solitary creatures, living only in the wild, and females are only able to get pregnant for a short time. these two at the zoo in atlanta have produced three cubs. >> we always give them a chance to mate first, and if that is not successful, we follow up with the artificial insemination. >> reporter: using this to help the creatures that have a hold on our heart. ann thompson, nbc news, new york. >> that is our broadcast as we start out a new week, thank you for joining us, i'm brian williams, and of course we hope to see you right back here tomorrow evening. good night.

right now at 6:00, a refinery under fire. we're live in richmond. what's expected to be a crowded community meeting. we're learning more information about the arrest of a principal and what investigators found inside his home. thanks for joining us on this monday. i'm raj mathieu. >> and i'm jessica aguirry. an investigation is u